Method of Collecting Information in Mobile Communication System

ABSTRACT

A mobile radio terminal includes a positional information acquisition unit to measure the position of the mobile radio terminal as position information using a Global Positioning System; a reception status acquisition unit to detect a handover failure; and a controller to send information of the position information and handover failure information to a base station.

This application is a Continuation application of U.S. patent application Ser. No. 10/700,483, filed on Nov. 5, 2003, which, in turn, has foreign priority based on Japanese Application No. 2002-330734, filed on Nov. 14, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radio communication system, and more particularly to the collection of measured values of reception statuses for the maintenance and optimization of a radio communication system.

2. Description of the Related Art

At present, efforts are being made to lower charges to be paid by subscribers to radio communication systems such as cellular phone systems, PHS, public radio LAN systems, etc. One of the efforts is to lower the operating costs of radio communication systems as much as possible. It is a large task for communication service providers to make less costly adjustments for the maintenance and optimization of radio communication systems.

The adjustments for the maintenance and optimization of radio communication systems include maintenance and adjustment activities that are performed to operate the radio communication systems stably without system failures over a long period of time. Items that need to be adjusted include, for example, the transmission power level of a radio base station and the tilt angle of an antenna.

The maintenance and adjustment of a radio communication system are generally performed based on an evaluation or examination process which employs a radio network design simulator. In order to increase the accuracy of a simulation, information about reception statuses that are measured in service areas (hereinafter referred to as “coverages”) of the radio communication system and information about positions where measured values are obtained are input to the design simulator.

In a CDMA system, for example, items of reception status information include the received signal quality and received signal intensity of a common pilot channel. These items of reception status information are useful items indispensable for system maintenance and adjustments because they serve as indexes for determining whether the services of the radio communication system are available to mobile radio terminals in the measured position or not.

Heretofore, it has been customary for a dedicated measuring vehicle or a dedicated measuring team to measure reception status information. FIG. 1 of the accompanying drawings is illustrative of a conventional process of collecting reception status information from a radio communication system. According to the conventional process, as shown in FIG. 1, coverages of the radio communication system in which radio base stations 91, 92, 93 are connected to network 90 are visited by members of measuring teams with reception status measuring vehicles 94. At each measuring spot, one reception status measuring vehicle 94 measures reception status information in the corresponding coverage. The measured reception status information is recorded in association with the positional information that is measured by position measuring device 94 a on reception status measuring vehicle 94.

Using the measured reception status information, the communication service provider performs maintenance and adjustments of the radio communication system to operate the radio communication system stably without fail.

According to another conventional process of collecting reception status information, the general mobile radio terminal owned by a user is used to measure reception status information, and the measured reception status information is collected from the mobile radio terminal (see, for example, JP2002-152104-A). According to this conventional process, reception status information can quickly and easily be collected without the need for the reception status measuring vehicle shown in FIG. 1.

The above conventional processes suffer the following problems:

The process of measuring reception status information using reception status measuring vehicles 94 shown in FIG. 1 needs a measuring team of members including a vehicle driver, a navigator, and a measuring person for driving each reception status measuring vehicle 94 and making measurements at desired spots. Expenses required to purchase and maintain the measuring vehicles and personnel expenses required to collect reception status information are large and present an obstacle to efforts to lower the operating cost of the radio communication system. The conventional process shown in FIG. 1 takes a lot of time to collect reception status information because all the coverages of the radio communication system need to be visited by a limited number of reception status measuring vehicles.

Reception status information in the coverages may be measured by many measuring teams without reception status measuring vehicles 94. However, such a modification requires increased labor costs though reception status measuring vehicles 94 are dispensed with.

In a CDMA radio communication system, when users are connected to the system, the load on the radio communication system, i.e., an interference quantity, changes, and hence coverages of the radio communication system vary with time. In order to keep stable coverages while the number of users is being progressively grown to turn the system into a mature one, it is necessary to repeatedly collect reception status information periodically. Consequently, the CDMA radio communication system requires a much greater cost for collecting reception status information than other systems because reception status measuring vehicles need to travel repeatedly periodically for collecting reception status information.

Another problem of the CDMA radio communication system is that while reception status information is being measured by reception status measuring vehicles as they travel through coverages, the user status in the measured areas may change.

According to the process of collecting reception status information with the general mobile radio terminals owned by users as disclosed in JP2002-152104-A, reception status information can be collected at a low cost because no reception status measuring vehicles and no measuring teams of various members are required. Since the coverages of the radio communication system are not visited by reception status measuring vehicles, but reception status information is measured by the mobile radio terminals owned by general users, a large amount of reception status information can be collected in a short period of time.

In the CDMA radio communication system, however, the reception status changes for various reasons, and changes in the reception status affect the operation of the radio communication system in various ways. For example, the reception status may change either with time or as the system load changes due to a user access congestion. Changes in the reception status may cause a change in the frequency of forced communication shutdowns from the network or a change in the frequency of handover failures.

The process disclosed in JP-2002-152104-A serves to collect only the relationship between reception status information and positional information, but fails to appropriately recognize causes of changes in the reception status and phenomena brought about by changes in the reception status.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a method of and a system for, and a mobile radio terminal for, collecting information related to operation of a radio communication system inexpensively and easily.

To achieve the above object, an information collecting system according to the present invention collects information used for adjustments in a radio communication system for performing user communications.

At least one mobile radio terminal monitors a communication status of user communications. When the mobile radio terminal detects as a trigger when the communication status has satisfied a predetermined condition, the mobile radio terminal acquires a reception status of a radio signal and the position of its own. The mobile radio terminal sends measured information including the reception status and the position to an information collecting server. The information collecting server receives the measured information from the mobile radio terminal and records therein the measured information which has been received.

Therefore, the communication service provider of the radio communication system can instantaneously obtain many reception statuses in respective positions in coverages in relation to the communication status, and can instantaneously and effectively perform maintenance and adjustments of radio communication facilities. Thus, man-hours and expenses involved in collecting information can be reduced.

Instantaneous and accurate system adjustments are significant in an area where many users are present. According to the present invention, many items of measured information of such an area are obtained, making it possible to make instantaneous and accurate system adjustments using may items of measured information in an area where the need for system adjustments is high.

In another information collecting system according to the present invention, an information collecting server sends trigger information simultaneously to at least one mobile radio terminal. When the mobile radio terminal receives the trigger information as a measuring trigger, the mobile radio terminal acquires a reception status of a radio signal and the position of its own. The mobile radio terminal sends measured information including the reception status and the position to an information collecting server. The information collecting server records the measured information received from the mobile radio terminal.

Accordingly, many items of measured information at respective spots at the same time can instantaneously be obtained for instantaneously and effectively performing maintenance and adjustments of radio communication facilities.

In still another information collecting system according to the present invention, an information collecting server sends trigger information simultaneously to at least one mobile radio terminal. The mobile radio terminal monitors a communication status of user communications. When the mobile radio terminal detects as a trigger when the communication status has satisfied a predetermined condition, or receives the trigger information as a measuring trigger, the mobile radio terminal acquires a reception status of a radio signal and the position of its own. The mobile radio terminal sends measured information including the reception status and the position to an information collecting server. The information collecting server records the measured information received from the mobile radio terminal.

The above and other objects, features, and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings which illustrate examples of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrative of a conventional process of collecting reception status information from a radio communication system;

FIG. 2 is a schematic view of a radio communication system according to an embodiment of the present invention;

FIG. 3 is a block diagram of a mobile radio terminal according to the embodiment of the present invention;

FIG. 4 is a flowchart of an operation sequence of the radio communication system and the mobile radio terminal according to the embodiment of the present invention for collecting reception status information;

FIG. 5 is a block diagram of a mobile radio terminal according to another embodiment of the present invention;

FIG. 6 is a flowchart of an operation sequence of the radio communication system and the mobile radio terminal according to the other embodiment of the present invention for collecting reception status information;

FIG. 7 is a block diagram of a mobile radio terminal according to still another embodiment of the present invention; and

FIG. 8 is a flowchart of an operation sequence of the radio communication system and the mobile radio terminal according to the still other embodiment of the present invention for collecting reception status information.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described in detail below.

FIG. 2 schematically shows a radio communication system according to an embodiment of the present invention. As shown in FIG. 2, the radio communication system has radio base stations 11, 12, 13, network 2, and information collecting server 1. Mobile radio terminals 21, 22 can be connected to the radio communication system. In FIG. 2, only two mobile radio terminals are shown though many mobile radio terminals can actually be connected to the radio communication system. Actually, the radio communication system has many radio base stations, but only three radio base stations are shown in FIG. 2 for illustrative purposes.

Mobile radio terminals 21, 22 comprise mobile terminals of cellular phone systems, PHS, public radio LAN systems, etc. that users use in the radio communication system. The users who use mobile radio terminals 21, 22 are users who have consented to provide information about their own positions and the reception status of radio signals from radio base stations for stable operation of the radio communication system.

FIG. 3 shows in block form details of mobile radio terminal 21 according to the present embodiment. Since mobile radio terminals 21, 22 are identical in arrangement, only mobile radio terminal 21 is shown in FIG. 3.

As shown in FIG. 3, mobile radio terminal 21 comprises positional information acquisition unit 31, reception status acquisition unit 32, communication status acquisition unit 33, time information acquisition unit 34, control unit 35, and display unit 36.

Positional information acquisition unit 31 acquires information representative of the position of mobile radio terminal 21. Positional information acquisition unit 31 measures its own position using a GPS (Global Positioning System), for example, and acquires the measured position as the positional information.

Reception status acquisition unit 32 acquires information representative of the reception status of a radio signal from a radio base station. The information representative of the reception status, i.e., the reception status information, is useful for the maintenance and adjustments of the radio communication system. Examples of the reception status information are Ec/Io (received signal power vs. interference power ratio per chip) indicative of a received signal quality of a common pilot channel in a CDMA radio communication system, and a received signal intensity in such a common pilot channel.

Communication status acquisition unit 33 can acquire information representative of the communication status of user communications. The information representative of the communication status, i.e., the communication status information, is information indicative of the status of communications that are performed using a radio signal. Examples of the communication status information are information indicating that the mobile radio terminal is unable to receive a radio signal from a radio base station and user communications are forcibly shut off, and information indicating that the mobile radio terminal is unable to make an outgoing call to another mobile radio terminal. Other examples of the communication status information are information indicating a handover failure and information indicating a communication throughput.

Time information acquisition unit 34 can acquire information representative of the time when reception status information is acquired, time information representative of the time when a reception status has started to be measured, and time information representative of the period of time for which a reception status has been measured.

When positional information, time information, and reception status information are acquired, control unit 35 sends the acquired information as measured information through either one of the radio base stations and network 2 to information collecting server 1. The measured information is information that includes positional information, time information, and reception status information.

When communication status information acquired by communication status acquisition unit 33 satisfies a predetermined condition, control unit 35 is triggered to instruct reception status acquisition unit 32 to acquire reception status information, instruct positional information acquisition unit 31 to acquire positional information, and instruct time information acquisition unit 34 to acquire a measuring start time and a measuring period of time. For example, when user communication such as a call or data communication are forcibly shut off, mobile ratio terminal 21 is triggered to acquire reception status information. Alternatively, mobile ratio terminal 21 may be triggered to acquire reception status information when the communication throughput becomes lower than a predetermined threshold value, or when a call is made to start user communications.

When control unit 35 receives information representative of a valuable point from information collecting server 1, control unit 35 displays the valuable point on display unit 36.

The valuable point is a point having a value corresponding to money, and is given to a user in return for the measured information provided by the user. An example of the valuable point is a point that can be used in electronic commerce on the Internet that is included in network 2. Another example of the valuable point is any of various cybercash and electronic money. Still another example of the valuable point is a point having a value in a core network of the radio communication system which is included in network 2, i.e., a point that can be used to offset a charge to be paid for using the radio communication system.

Display unit 36 displays valuable point information according to an instruction from control unit 35.

Radio base stations 11, 12, 13 are facilities for sending radio signals to and receiving radio signals from mobile radio terminals 21, 22, and comprise base stations in cellular phone systems or PHSs, or access points of radio LAN systems or the like.

Network 2 comprises a core network of the radio communication system according to the present embodiment, e.g., a network made up of mobile exchanges of a cellular phone system. In the present embodiment, network 2 also includes the Internet connected through a gateway (not shown).

Information collecting server 1 comprises a computer such as a workstation or the like. Information collecting server 1 receives and records measured information transmitted from mobile radio terminals 21, 22. When information collecting server 1 receives and records measured information transmitted from mobile radio terminals 21, 22, information collecting server 1 sends valuable point information that is to be given to the users of mobile radio terminals 21, 22, i.e., transmission sources, through network 2 and a radio base station to mobile radio terminals 21, 22.

FIG. 4 shows an operation sequence of the radio communication system and the mobile radio terminal according to the present embodiment for collecting reception status information. In FIG. 4, operation of only mobile radio terminal 21 and information collecting server 1 is illustrated.

Dedicated software is installed beforehand in the mobile radio terminal of a user who has consented to provide measured information including information about reception status information and positional information in return for the acquisition of a valuable point. The mobile radio terminal with the dedicated software installed is used as mobile radio terminals 21, 22. With the dedicated software installed, mobile radio terminals 21, 22 can automatically operate as follows:

As shown in FIG. 4, mobile radio terminal 21 monitors the communication status of user communications, and detects as a trigger when communication status information has satisfied a predetermined condition (step 101). When mobile radio terminal 21 detects the trigger, mobile radio terminal 21 measures a reception status and acquires reception status information indicative of the measured reception status (step 102). At this time, mobile radio terminal 21 also acquires time information. Instead of the operation in steps 101, 102, mobile radio terminal 21 may continuously measure a reception status at all times and, when mobile radio terminal 21 detects a trigger, it may use the reception status measured at the time for a subsequent process.

Then, mobile radio terminal 21 measures its own position using a GPS, and acquires positional information indicative of the measured position (step 103). However, mobile radio terminal 21 may not be able to acquire positional information depending on its position or environment. In that case, mobile radio terminal 21 may use positional information which it has acquired at a past time closest to the present time. Moreover, mobile radio terminal 21 should preferably add information indicative of low reliability to the positional information. Then, mobile radio terminal 21 sends measured information including the positional information, the time information, and the reception status information to information collecting server 1 (step 104).

In order to reflect the measured information early for system adjustments, mobile radio terminal 21 should preferably send the measured information including the reception status information and the positional information to information collecting server 1 immediately after mobile radio terminal 21 has acquired the reception status information and the positional information. If a forced shutdown of user communication or a handover failure is used as a trigger, then mobile radio terminal 21 is unable to send the measured information to information collecting server 1 immediately after the trigger is detected. In this case, mobile radio terminal 21 may send the measured information after the circuit becomes available again.

Information collecting server 1 receives the measured information from mobile radio terminal 21, and records the received information in its own memory (step 105). Actually, since information collecting server 1 receives measured information similarly from a plurality of mobile radio terminals, information collecting server 1 collects reception status information in various positions in coverages.

The measured information collected by information collecting server 1 is related to various operations of the radio communication system depending on trigger conditions. Consequently, not only a map representing an association between positions and reception statuses, but also maps related to various statuses are obtained. For example, a map of information that is acquired when user communications are forcibly disconnected is useful for estimating an area where a radio-wave arrival status is poor. A map of information that is acquired when a handover failure occurs is useful for estimating a position where there is a coverage interruption between radio base stations. A map of information that is acquired when a throughput is lower than a predetermined threshold value is useful for estimating a position where a communication quality is poor. A map of information that is acquired when a call is made is useful for estimating a position where many users are present.

The measuring time represented by the time information contained in the measured information is useful to estimate a time-dependent change in the communication status or the reception status.

Then, information collecting server 1 gives a valuable point to the user of mobile radio terminal 21, and sends valuable point information representative of a value (valuable point) given in return for the information provided by the user, to mobile radio terminal 21 (step 106). For non-delay system operation, information collecting server 1 should preferably send valuable point information is sent to mobile radio terminal 21 immediately after the measured information from mobile radio terminal 21. If a traffic buildup is to be prevented, however, information collecting server 1 may delay the timing to send valuable point information. For example, information collecting server 1 may collect several items of valuable point information and thereafter send the collected items of valuable point information. Information collecting server 1 may also send collected items of valuable point information late at night.

Actually, a valuable point may be given by different processes depending on the form of the variable point. For example, if a valuable point can be used to offset a charge to be paid for using the radio communication system, then it may be recorded and managed in information collecting server 1, a billing center (not shown), or a dedicated valuable point managing server. If a valuable point is in the form of electric money related to a bank account, then the valuable point may be sent to a bank server.

When measure information is thus collected by information collecting server 1, core network 2 of the radio communication system uses the collected information for the maintenance of radio base stations 11, 12, 13 and for adjusting various parameters including the transmission output power and the tilt angles of antennas.

According to the present embodiment, as described above, when a predetermined communication status is achieved, the mobile radio terminals of users acquire reception state information and positional information, and send measured information including the reception state information and the positional information to information collecting server 1. Therefore, the communication service provider can instantaneously obtain many items of measured information related to the communication status by giving inexpensive valuable points to users, and can instantaneously and effectively perform maintenance and adjustments of the radio base stations with reduced man-hours and expenses.

According to the present embodiment, furthermore, since many items of measured information can instantaneously be collected and reflected for system maintenance and adjustments, the measured information can provide outstanding advantages while the number of users is being progressively grown in a radio communication system, e.g., a CDMA radio communication system, where coverages change due to a load status or an interference quantity on radio circuits when mobile radio terminals are connected.

Moreover, instantaneous and accurate system adjustments are significant in an area where many users are present. Since many items of measured information of such an area are obtained, it is possible to make instantaneous and accurate system adjustments using many items of measured information in an area where the need for system adjustments is high.

According to the present embodiment, measured information is acquired only from the mobile radio terminals of users who have consented to provide positional information and reception status information. Therefore no information is automatically acquired from users who do not want to send positional information and reception status information to the communication service provider. The users are thus free from undue concerns from the standpoint of their privacy and electric power consumption by their mobile radio terminals.

Another embodiment of the present invention will be described below.

A radio communication system according to the present embodiment is identical in arrangement to the radio communication system shown in FIG. 2. However, the radio communication system according to the present embodiment operates differently from the operation sequence shown in FIG. 4 in that a trigger for mobile radio terminals 21, 22 to obtain measured information is given from information collecting server 1 simultaneously to a plurality of mobile radio terminals.

FIG. 5 shows in block form a mobile radio terminal according to another embodiment of the present invention. The mobile radio terminal shown in FIG. 5 differs from the mobile radio terminal shown in FIG. 3 in that it has trigger information reception unit 37 instead of communication status acquisition unit 33.

Trigger information reception unit 37 receives trigger information from information collecting server 1, and sends the received trigger information to control unit 35. The trigger information is information for triggering the measurement of information. According to the present embodiment, information collecting server 1 can send trigger information simultaneously to a plurality of mobile radio terminals in order to cause the mobile radio terminals to start measuring information.

Control unit 35 is triggered by the reception of trigger information from information collecting server 1 to instruct reception status acquisition unit 32 to measure a reception status, instruct positional information acquisition unit 31 to measure positional information, and instruct time information acquisition unit 34 to acquire a measuring time, etc.

FIG. 6 shows an operation sequence of the radio communication system and the mobile radio terminal according to the present embodiment for collecting reception status information. In FIG. 6, operation of only mobile radio terminal 21 and information collecting server 1 is illustrated.

Dedicated software is installed beforehand in the mobile radio terminal of a user who has consented to provide measured information including reception status information and positional information in return for the acquisition of a valuable point. The mobile radio terminal with the dedicated software installed is used as mobile radio terminals 21, 22.

As shown in FIG. 6, information collecting server 1 sends trigger information simultaneously to a plurality of mobile radio terminals (step 201). For example, information collecting server 1 sends trigger information in a special time zone where a reception status is to be observed, such as a time zone in which the system load is statistically high or a time zone in which the system load is statistically low. In response to the trigger information, mobile radio terminal 21 measures a reception status and acquires the measured reception status as reception status information (step 202). At this time, mobile radio terminal 21 also acquires time information.

The subsequent processing in steps 203 through 207 is the same as the processing in steps 103 through 107 shown in FIG. 4.

The measured information collected by information collecting server 1 has been simultaneously acquired by a plurality of mobile radio terminals which have been triggered by the reception of the trigger information. Therefore, not only a map representing an association between positions and reception statuses, but also reception statuses in various positions in coverages at the same time are acquired. The information thus acquired is useful to estimate how changes in the reception statuses in the respective positions are related.

According to the present embodiment, as described above, mobile radio terminals are triggered by trigger information sent from information collecting server 1 simultaneously to a plurality of mobile radio terminals, to acquire reception status information and positional information, and send measured information including the reception state information and the positional information to information collecting server 1. Therefore, the communication service provider can instantaneously obtain many items of measured information at respective spots at the same time by giving inexpensive valuable points to users, and can instantaneously and effectively perform maintenance and adjustments of the radio base stations with reduced man-hours and expenses.

Another embodiment of the present invention will be described below.

A radio communication system according to the present embodiment is identical in arrangement to the radio communication system shown in FIG. 2. However, the radio communication system according to the present embodiment operates differently from the operation sequence shown in FIG. 4 in that triggers for mobile radio terminals 21, 22 to obtain measured information include a trigger given from information collecting server 1 simultaneously to a plurality of mobile radio terminals, as shown in FIG. 4, and a trigger which is detected by the mobile radio terminals themselves as shown in FIG. 4.

FIG. 7 shows in block form a mobile radio terminal according to this embodiment of the present invention. The mobile radio terminal shown in FIG. 7 differs from the mobile radio terminal shown in FIG. 3 in that it has both communication status acquisition unit 33 and trigger information reception unit 37. Communication status acquisition unit 33 shown in FIG. 7 is identical to communication status acquisition unit 33 shown in FIG. 3, and trigger information reception unit 37 shown in FIG. 7 is identical to trigger information reception unit 37 shown in FIG. 5.

When communication status information is acquired as a trigger by communication status acquisition unit 33 or when trigger information is received by trigger information reception unit 37, control unit 35 is triggered to instruct reception status acquisition unit 32, communication status acquisition unit 33, and time information acquisition unit 34.

FIG. 8 shows an operation sequence of the radio communication system and the mobile radio terminal according to the present embodiment for collecting reception status information. In FIG. 8, operation of only mobile radio terminal 21 and information collecting server 1 is illustrated.

Dedicated software is installed beforehand in the mobile radio terminal of a user who has consented to provide measured information including reception status information and positional information in return for the acquisition of a valuable point. The mobile radio terminal with the dedicated software installed is used as mobile radio terminals 21, 22.

As shown in FIG. 8, information collecting server 1 sends trigger information simultaneously to a plurality of mobile radio terminals (step 301), or mobile ratio terminal 21 detects as a trigger when communication status information has satisfied a predetermined condition (step 302).

When either trigger is generated, mobile ratio terminal 21 measures a reception status and acquires it as reception status information (step 303). At this time, mobile radio terminal 21 also acquires time information.

The subsequent processing in steps 304 through 308 is the same as the processing in steps 103 through 107 shown in FIG. 4.

The measured information collected by information collecting server 1 is related to various operations of the radio communication system or obtained at the same time, depending on trigger conditions. Consequently, not only a map representing an association between positions and reception statuses, but also maps related to various statuses or maps representative of reception statuses in various positions in coverages at the same time are acquired.

According to the present embodiment, as described above, mobile radio terminals are triggered by a certain communication status or trigger information sent from information collecting server 1 simultaneously to a plurality of mobile radio terminals, to acquire reception status information and positional information, and send measured information including the reception state information and the positional information to information collecting server 1. Therefore, the communication service provider can instantaneously obtain many items of measured information related to communication statuses and measured information at respective spots at the same time by giving inexpensive valuable points to users, and can instantaneously and effectively perform maintenance and adjustments of the radio base stations with reduced man-hours and expenses.

While preferred embodiments of the present invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. 

What is claimed is:
 1. A mobile radio terminal, comprising: a positional information acquisition unit to measure a position of the mobile radio terminal as position information using a GPS (Global Positioning System); a reception status acquisition unit to detect a handover failure; and a controller to send information of the position information and handover failure information to a base station.
 2. The mobile radio terminal according to claim 1, wherein the mobile radio terminal sends the position information and the handover failure information if a user of the mobile radio terminal has consented to provide the position information and the handover failure information.
 3. The mobile radio terminal according to claim 1, further comprising a time acquisition unit that detects a time that the handover failure occurred, wherein the controller also sends time information along with the position and handover failure information.
 4. A base station, comprising: a transmitter to send signals to a mobile radio terminal; and a receiver to receive position information measured by the mobile radio terminal using a Global Positioning System and a handover failure information from the mobile radio terminal.
 5. The base station according to claim 4, wherein the position information and the handover failure information are transmitted from the mobile radio terminal if a user of the mobile radio terminal has consented to provide the position information and the handover failure information.
 6. A method of collecting information in a mobile communication system, the method comprising, in a mobile radio terminal: detecting a handover failure; measuring a position of the mobile radio terminal using a GPS (Global Positioning System); and transmitting information of the handover failure and the position of the mobile radio terminal to a base station.
 7. The method according to claim 6, wherein the position and handover failure information is transmitted if a user of the mobile radio terminal has consented to provide the position information and the handover failure information.
 8. The method according to claim 6, further comprising sending the handover failure and position information to an information collecting server.
 9. The method according to claim 6, further comprising: detecting a time of the handover failure; and transmitting the time information to the base station along with the handover failure and position information.
 10. A non-transitory storage medium tangibly embodying a set of computer-readable instructions causing a processor in a mobile radio terminal to execute the method of claim
 6. 11. A method of collecting information in a mobile communication system, the method comprising, in a base station, receiving position information measured by a mobile radio terminal using a GPS (Global Positioning System), along with handover failure information from the mobile radio terminal.
 12. The method according to claim 11, wherein the position and handover failure information is transmitted if a user of the mobile radio terminal has consented to provide the position information and the handover failure information.
 13. The method according to claim 11, wherein time information of the handover failure is also received by the base station.
 14. The method according to claim 11, further comprising sending the handover failure and position information to an information collecting server.
 15. The method according to claim 14, further comprising receiving: the handover failure and position information in an information collecting server; and storing the handover failure and position information in a storage device in the information collection server.
 16. A non-transitory storage medium tangibly embodying a set of computer-readable instructions causing a processor in a base station to execute the method of claim
 14. 17. A non-transitory storage medium tangibly embodying a set of computer-readable instructions causing a processor in an information collection server to execute the method of claim
 15. 